Yup you can take anything hazardous with you as long as its in your suitcase. Trimmers, straighteners, knives, machettes, Nitrus Oxide, Liquid Nitrogen
As they ask you when you check the bag in, is there any hazzardous substances in your suitcase.Even in your hand luggage it should be ok, I always take my razor on-board and it hasn't caused a problem and I'm flying at least once a month.
Razor, through a UK airport? You'll be lucky.
February - Dubai, Dublin
March - Dublin
June - Dublin, Belfast
July - Dublin, Edinburgh
August - Marbella
Most of those were hand luggage trips all with my Gillette Fusion razor, through UK airports. Not really luck is it?
They are fine with razors as a lot of business people travel last minute with hand luggage only.